Vortex Dynamics in Superconducting Stripes with Star-Shaped Defects under Applied Currents and Magnetic Fields
Davi G. M. Santos¹, Talles N. Benites¹, Edson Sardella², Rafael Zadorosny¹
¹São Paulo State University (UNESP), School of
Engineering, Ilha Solteira - SP;
²São Paulo State University (UNESP), School of
Sciences, Bauru - SP.
Abstract:
In type-II superconductors, vortices allow the material to maintain superconductivity under high magnetic fields; however, their movement results in energy dissipation. This can be mitigated by introducing pinning centers—defects within the superconducting matrix that immobilize vortices and enhance performance [1]. In this work, we investigate the vortex dynamics in a two-dimensional semi-infinite superconducting film containing star-shaped blind holes acting as pinning centers, under applied transport currents and magnetic fields [2]. The system is modeled within the framework of the generalized time-dependent Ginzburg-Landau (TDGL) equations, using periodic boundary conditions, and numerically solved using a FORTRAN-90 code [3]. Our simulations reveal current crowding effects at the vertices of the star-shaped defects. Despite this concentration, vortex entry and motion predominantly occur along the central axis of the sample, owing to the geometrical symmetry. Interestingly, in the absence of an external magnetic field, we observe the nucleation and annihilation of vortex–antivortex pairs within the defect region. Furthermore, analysis of the current–voltage (IV) characteristics indicates the emergence of two distinct resistive states at higher magnetic fields, reflecting complex vortex dynamics influenced by the engineered defect structure.
Acknowledgements:
CNPq. grant 310428/2021-1, and CAPES, financial code 001.
References:
[1] S. Readts, et al., PRB 70 (2004) 024509.
[2] R. C. Santos, et al., Phys. Lett. A 458 (2023) 128595.
[3] W. D. Gropp, Journal of Computational Physics 123 (1996) 254.
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